package day07;
import java.util.Random;
public class VerificationCode {
    public static void main(String[] args) {
        String code = generateVeriCode(4);
        System.out.println("验证码:"+code);
    }
    public static String generateVeriCode(int len){
        String code = "";
        char[] chs = {'a','b','c','d','e','f','g','h','i',
                'j','k','l','m','n','o','p','q','r','s','t',
                'u','v','w','x','y','z','A','B','C','D','E',
                'F','G','H','I','J','K','L','M','N','O','P',
                'Q','R','S','T','U','V','W','X','Y','Z','1',
                '2','3','4','5','6','7','8','9','0'};
        Random rand = new Random();
        for (int i = 1; i <= len; i++) {
            int index = rand.nextInt(chs.length);
            code += chs[index];
        }
        return code;
    }
}
